The field of the present invention relates to optical devices incorporating distributed optical structures. In particular, distributed optical structures with diffractive elements thereof distributed among multiple channel waveguides of an optical apparatus are disclosed herein.
An optical apparatus comprising an optical element having one or more distributed optical structures (i.e., one or more sets of diffractive elements) may be configured to provide a variety of optical functionality, including spectral filtering, temporal encoding, and others. Such devices, if single mode, may enable nearly complete control of amplitude and phase of optical signals to achieve filtering, encoding, routing, and other functions. Multimode devices may enable similar control. Examples of such devices may be found in the references cited herein.
This application may be related to subject matter disclosed in: non-provisional application Ser. No. 09/811,081 entitled xe2x80x9cHolographic spectral filterxe2x80x9d filed Mar. 16, 2001 in the name of Thomas W. Mossberg; provisional App. No. 60/190,126 filed Mar. 16, 2000; provisional App. No. 60/199,790 filed Apr. 26, 2000; provisional App. No. 60/235,330 filed Sep. 26, 2000; provisional App. No. 60/247,231 filed Nov. 10, 2000; non-provisional application Ser. No. 10/653,876 entitled xe2x80x9cAmplitude and phase control in distributed optical structuresxe2x80x9d filed Sep. 2, 2003 in the names of Christoph M. Greiner, Dmitri Iazikov, and Thomas W. Mossberg; non-provisional application Ser. No. 10/229,444 entitled xe2x80x9cAmplitude and phase control in distributed optical structuresxe2x80x9d filed Aug. 27, 2002 in the names of Thomas W. Mossberg and Christoph M. Greiner, now U.S. Pat. No. 6,678,429 issued Jan. 13, 2004; provisional App. No. 60/315,302 filed Aug. 27, 2001; provisional App. No. 60/370,182 filed Apr. 4, 2002; provisional App. No. 60/468,479 filed May 7, 2003; provisional App. No. 60/486,450 filed Jul. 10, 2003; non-provisional application Ser. No. 10/794,634 entitled xe2x80x9cTemperature-compensated planar waveguide optical apparatusxe2x80x9d filed Mar. 5, 2004 in the names of Dmitri Iazikov, Thomas W. Mossberg, and Christoph M. Greiner; and provisional App. No. 60/452,834 filed Mar. 6, 2003. Each of said patent and said provisional and non-provisional patent applications is hereby incorporated by reference as if fully set forth herein.
An optical apparatus comprises an optical element having formed therein at least one set of diffractive elements and at least two channel optical waveguides. Each channel optical waveguide substantially confines in two transverse spatial dimensions an optical signal propagating therein. Diffractive elements of each set of diffractive elements are distributed among diffractive element subsets corresponding to each of the multiple channel waveguides. Each diffractive element set routes, between a corresponding pair of optical ports, those corresponding portions of an optical signal propagating within the optical element that are received by multiple channel waveguides and back-diffracted within the receiving channel waveguides by corresponding diffractive element subsets. The channel optical waveguides are arranged so that an optical signal entering the optical element at an input optical port first propagates through a region of the optical element between the input optical port and the first ends of the channel waveguides and is then incident on and received at least in part by multiple channel optical waveguides. The channel optical waveguides are arranged so that the corresponding routed portions of optical signal exiting the optical element at an output optical port first propagate through a region of the optical element between the first ends of the channel waveguides and the output optical port.
Channel waveguides may route, between a corresponding pair of optical ports, portions of an optical signal transmitted by the diffractive element subsets, by redirection therein or transmission therethrough. Relative spatial arrangement of the ends of the channel waveguides and corresponding relative phase shifts imparted on back-diffracted portions, transmitted portions, and/or redirected portions of the optical signal in the channel waveguides may define at least in part a relative spatial arrangement of corresponding pairs of optical ports. The ends of the channel waveguides may be curved, flared, tapered, segmented, or otherwise adapted for optical coupling. Relative phase shifts may be imparted by waveguide position, length, modal index, longitudinal positions of diffractive element subsets, static phase shifters, phase modulators, and so forth. The arrangement of the diffractive elements may determine at least in part spectral and/or temporal characteristics of the optical apparatus, which may be substantially independent of temperature and/or polarization, or may exhibit designed dependence(s) on temperature and/or polarization. The optical apparatus may include multiple sets of diffractive elements. Routing of optical signals may be imaged, or non-imaged. Two or more similar optical devices may be cascaded, optical output of one device serving as optical input of another.
Objects and advantages pertaining to optical structures distributed among multiple optical waveguides may become apparent upon referring to the disclosed embodiments as illustrated in the drawings and disclosed in the following written description and/or claims.